A non-exhaustive but substantial list of ebook stores.
Search Most of Them All at Once Here
Amazon.com
Amazon offers Kindle Edition eTextbooks for purchase or rent. Not every book works with every Kindle device or app, so check compatibility on the product detail page.
eCampus.com
Sells and rents online textbooks via VitalSource. You can access your books through the VitalSource Bookshelf app, available on Android, iOS, Microsoft and Kindle stores.
TextbookX
View purchased and rented books via the browser-based TextbookX eReader. Some ebooks are accessed via CourseSmart or VitalSource.
Read Also: eTextbooks: Ways to Pay Less
Chegg
Buy or rent books and view them with the Chegg eReader app for desktop and mobile devices. Like other apps, it offers features like search, highlighting and study tools.
BiggerBooks
Books can be accessed online via the BiggerBooks eBook Library and offline via the VitalSource app.
CengageBrain
eBook rentals are available in 4-, 6- and 12-month blocks and can be accessed via web browsers and the Cengage mobile app for Android and iOS.
Textbooks.com
Textbooks.com sells and rents eTextbooks that can be accessed via various platforms (depending on the book), including its own Bookshelf Reader, VitalSource BookShelf, CourseSmart and Adobe Digital Editions.
Apress
Specializing in books for developers and IT professionals, Apress sells ebooks with lifetime access. They can be viewed on browsers via MyBookshelf and downloaded in PDF or ePUB format for reading on Kindle, Kobo, iPad and other devices (ePUB files can be converted into Kindle format).
eBooks.com
Buy ebooks direct and read them via eBooks.com’s Online Reader. You can also download ePUB and PDF files to your computer, install the Ebook Reader app on your mobile phone or use a dedicated eReader device that’s compatible with Adobe DRM.
InformIT
InformIT ebooks cover information technology disciplines and are available in ePUB, MOBI and PDF formats. Imprints include Adobe Press, Cisco Press and Microsoft Press.
Elsevier
Elsevier sells science, tech and medical publisher ebooks in PDF, ePUB, MOBI and VitalSource/VSB formats.
Apple iTunes iBook
Purchase and download books for use with the Apple Books app on your iPhone, iPad or Mac. If you have Windows, you can access books via iTunes.
RedShelf
RedShelf offers digital textbook rentals and lifetime access purchases. Books are viewable online or off via the browser-based RedShelf cloud reader or the RedShelf mobile app for Android or iOS.
Palgrave
Palgrave ebooks are available in ePUB and PDF formats, and can be read online, on mobile devices and eReaders. If you have an Amazon Kindle, you can import PDF files into MOBI format or convert ePUB to Kindle format.
VitalSource
VitalSource offers both textbook purchases and rentals. Books are in PDF or ePUB format and viewable online and offline via the BookShelf app, which is compatible with Mac and Window computers, Android and iOS mobile devices, Chromebooks and Kindle Fire devices.
Pearson
Pearson offers eText subscriptions for a wide variety of subjects. eTexts can be viewed online and offline with the Pearson eText app, available for Android, iOS and web browsers like Chrome, Firefox and Safari.
Springer
Springer publishes digital textbooks covering medical, technical and scientific disciplines. Formats include ePUB and PDF, which work on web browsers, mobile devices and many eReaders. They can also be converted into Amazon Kindle format.
McGraw-Hill
bbMcGraw-Hill offers both eTextbook rentals and purchases. They’re viewable in the free ReadAnywhere app, which offers both online and offline reading as well as notetaking and highlighting.
Here are some additional sources you can try for ebooks.
University of Minnesota Open Textbook Library
Oregon State University Open Textbooks
MIT Open Courseware Online Textbooks